Refactor instance update flow, asset registry, and texture IO

- Renamed AddInstanceRequest to UpdateInstanceRequest; unified add/update logic for GPU instances
- Introduced UpdateGPUInstanceSystem to handle changed MeshInstance components
- Replaced QueryBuilder.Create() with QueryBuilder.New() for consistency
- Switched versioning in ChunkView HasChanged/HasStructuralChanged to uint
- Added extension-to-AssetType mapping in AssetHandlerRegistry
- Changed TextureAssetHandler/Processor to use nint for image data
- Enhanced DDS cache: read mipmap count, handle invalid files
- Updated ProjectBrowserViewModel to use IAssetRegistry
- Upgraded Misaki.HighPerformance and System.IO.Hashing packages
- Set DependencyChainCapacity in JobSchedulerDesc
- Fixed instance buffer logic in GhostRenderPipeline
- Miscellaneous cleanups and namespace improvements

src/Runtime/Ghost.Entities/System.cs

@@ -28,11 +28,17 @@ public abstract class SystemBase : ISystem
 {
     private UnsafeList<int> _requiredQueries;
 
+    /// <summary>
+    /// Gets the world that the system is running on currently.
+    /// </summary>
     public World World
     {
         get; init;
     } = null!;
 
+    /// <summary>
+    /// Gets the last version that the system update.
+    /// </summary>
     public uint LastSystemVersion
     {
         get; internal set;